Yes, from my understanding any team can claim a player off another team's practice squad.
However, that player then is added to the acquiring team's active roster. The fact that these
players all ready cleared waivers shows that there wasn't huge interest in them, but there is
still a chance another team may add them later on in the year.

I'm glad to see Gurley, West, Harrell and Dominguez are still part of the team at this time.

When a team wants to sign a player off another teams PS, the player has to agree to the transaction. A player CAN refuse the second teams offer and stay on the PS. So in a sense, yes a 'right of first refusal' does exist: If a player is on Team A's practice squad, and Team B makes that player an offer to be on their 53 man roster, Team A can offer the player a spot and elevate them from the squad. But that means releasing a player currently on the 53. Just about every player on a PS wants to be on an active roster pretty bad, so when an offer comes along most players take it and sign to Team B.